cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jonathan Ellis (Commented) (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-3287) limit row cache size as a proportion of sstable size
Date Fri, 30 Sep 2011 20:40:45 GMT


Jonathan Ellis commented on CASSANDRA-3287:

Key cache and row cache are both per-CF, not per-SSTable.

We plan to make the caches global in CASSANDRA-3143.
> limit row cache size as a proportion of sstable size
> ----------------------------------------------------
>                 Key: CASSANDRA-3287
>                 URL:
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Yang Yang
>            Priority: Minor
> I was debugging some problem,
> then I found that my memory size increased extremely fast, 
> and finally reached my old gen total, and then CMS was starting all the time, back-to-back.
> even after I force a full GC, the old gen space is not decreasing any.
> so I invoked invalidate cache from jmx, then did GC, now the old gen size went down.
> so it's due to row cache.
> but my row cache is really not that big.
> then I realized that it's due to too many small sstables. each sstable has the same size
row cache. then for the smaller sstables, it's too favorable: they have a higher retention
ratio, while in fact we can assume that the hit ratio should be the same for all sstables,
particularly if you have a random access pattern.
> if this makes sense, I can put in a simple patch on calling the constructor of the rowcache

This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:!default.jspa
For more information on JIRA, see:


View raw message